Plate latch and guide system

ABSTRACT

Latch and guide system for gripping steel plate and the like while it is edge-formed. A pulley system is driven to apply tension to cables which actuate gripping clamps. The clamps travel within channel guides along the length of the system and restrain the plate from lateral movement.

This application is a continuation of application Ser. No. 06/198,766,filed Oct. 20, 1980, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a system and apparatus for restraining lateralmovement of metal plates and sheet and the like while they are beingconveyed longitudinally through various stations as their edges areworked upon. Examples of such operations are edge trimming and formingof plates prior to shaping into large diameter pipe, or in weldingreenforcing elements thereon, or performing other fabricating operationswherein skewing or misalignment of the plate may occur and would beundesirable and detrimental to subsequent operations.

2. Description of Prior Art

It is well known to use clamping or gripping means on the trailing edgesof metal sheet and plate to restrain lateral movement of a flat sectionas it is passed through a metal working operation. In such arrangementsthe gripping elements may be positioned within channels or other guidingarrangements to permit forward and reverse movement of the clamps andplates, and at the same time to prevent lateral movement thereof. Thesesystems have not always been satisfactory because of the difficulty ofmaintaining adequate gripping pressure while the plate section movesforward and maintaining it in the proper position, or otherwisecontrolling the plates and clamps, while they are subjected to thetensions and side forces present during fabrication of the plate or anyother working operation. Further, the various types of apparatuspresently in use are expensive and complicated to operate.

U.S. Pat. No. 4,015,702 is to a method and apparatus for successivelyconveying large metal plates of varying sizes to a particular positionwhere a welding operation of the like may be performed. It utilizes aguide beam in which gripping elements are used on the forward and rearedges of each plate section. However, the gripping elements are intendedto be fastened to channel beam guides and the channel beams travelthrough the work area. Moreover, the channel beams are moved by a rackand pinion arrangement which is cumbersome and far too slow to bepractical for an operation involving edge forming and trimming of aplate for use in making large diameter pipe.

U.S. Pat. No. 4,090,703 discloses apparatus for feeding rectangularmetal sheets to a cupping press in which can body blanks are cut anddrawn from the metal sheets. Several sheets feeding mechanisms areprovided along a conveyor table. Endless chains and feedfingerarrangements move the metal sheets. The trailing edge of the sheet isengaged by a reciprocating feedfinger arrangement to advance andaccurately position a sheet section from which blanks are to be stamped.The scrap is discharged froom the press or table on which the stampingtakes place. A plurality of longitudinally extending laterally narrowstrips are provided to support the sheet sections which are to beblanked. There are also three separate feed units. The metal sectionsare not subjected to the lateral forces and torque comparable to rollforming or other fabricating operations which would cause misalignmentand skewing during passage through the machine.

U.S. Pat. No. 1,986,857 discloses a complicated machine for foldingcorrugated paper blanks during their passage across an operating table.Although chain and pulley arrangements are disclosed, the nature of thematerials which are being worked upon, that is, corrugated paper, andthe problems involved are different than those encountered by applicant.The equipment employed in the patent is primarily a feeding device andwould not be useful for handling steel plate.

Accordingly, the art does not suggest a simple, low cost and efficientarrangement such as the present invention.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a diagrammatic view in perspective of the latch and guidesystem in a typical application within the scope of the invention.

FIG. 2 is a longitudinal view partly in section and broken away inplaces showing the clamps, pulleys and cable means of one usefulembodiment of the invention while the plate is engaged by the clamps andheld in place for working.

FIG. 3 is a view, partly in section, along line 3--3 of FIG. 2 lookingin the direction of the arrows.

FIG. 4 is a fragmentary view of the top portion of a clamp of theinvention and looking in a direction opposite to that of FIG. 3.

FIGS. 5A through 5H show various operating positions of the latch andguide system and apparatus of the invention during the sequence of stepsemployed in the operation.

FIGS. 6A, 6B and 6C are diagrammatic longitudinal views of anadvantageous alternative arrangement of the clamp and pulley assembly ofthe invention.

FIG. 7 is a view partly in section along line 7--7 of FIG. 6B looking inthe direction of the arrows.

FIG. 8 is a side view partly in section of a clamp of the type useful inthe various embodiments of this invention and showing the forces exertedby the jaws of the clamp when engaging a plate.

DETAILED DESCRIPTION OF THE INVENTION

The drawings show the working of a steel plate section 10 which is to beedge trimmed and subjected to various edge beveling, planing and rollforming operations. Such an operation subjects the plate to lateralforces which if not controlled results in skewing and misalignment ofthe plate. Machine M is a roll forming machine adapted to bend, trim,bevel and further bend the edges of plate 10 preparatory to passing theplate along a conventional runout table 24, having a plurality of spacedapart rolls 26, and on to a pipe forming operation (not shown).

Elements C₁ and C₂ are tail clamps and lead clamps, respectively, whichare shaped in the manner shown in the drawings (see FIGS. 2, 3, 4, and8) so that the mouth portions thereof are adpated to engage the trailingand leading edges of plate 10.

Clamp C₁ is hinged at 12 so that it may pivot at that point as requiredduring the various stages of operation of the invention. Clamp C₂ ishinged at 14 in the same manner for the same purpose.

Cable or chain means are provided to move clamps C₁ and C₂ as requiredfor the various operations within the system. Clamp C₁ is attached tocable or chain R₁ or any other suitable wire rope or the like which cantraverse the pulley assembly hereafter described and apply the forcesrequired to cause sufficient gripping pressure on the plate 10 as ittravels along its path. A similar cable or chain arrangement R₂ isprovided to actuate clamp C₂ and move it along its path of travel.

The hinge or pivot arrangement for clamps C₁ and C₂ at points 12 and 14,respectively, each include a base bar 20 affixed to each of the cablesR₁ and R₂ as well as to the clamp which is suppprts. Tension springs 18are fastened at one of their ends to the opposite ends of base bar 20and extend to the nearest face of the clamp supported on the particularbar with which it cooperates. Springs 18 are designed to maintain theclamps in an erect position when the clamps are not engaged and also toyield or depress when a plate contacts the clamp near its top at otherthan its open mouth or when the clamp contacts a stop element. Othermeans of holding the clamp erect may be used to accomplish the requiredfunctions such as compression springs, detents or the like.

The face of each clamp adapted to engage plate 10 has an open mouth orjaw section 21 adapted to receive plate 10 or the like to effectengagement bewteen the two elements. Advantageously, teeth 22 may beused in the clamps to insure a tighter grip on plate 10 at the area ofengagement.

The clamps designated C and described herein, including the jaw-likemouth 21, upper teeth 22 and the hinge or pivot point 12 or 14, areimportant features of the invention. As is disclosed in FIG. 8, the jawsadvantageously have upper and lower inserts 16 and 17 respectively, oftool steel which can be changed as required to accommodate wear or therequirements of a particular product.

One advantage of the design of clamp C is that it can firmly grasp theedge of a plate while a relatively low force is applied to providetension to the cable means which actuates the clamp to cause it to movealong its path of travel. As will be noted in FIG. 8, F₂ and F₃ are therespective forces applied by the upper and lower jaws 16 and 17 of aclamp when in engagement with the edge of a plate. 1₁ is the lever armextending the distance from a pivot point on base bar 10 attached to thecable to the plate side which lower jaw 17 is in contact. 1₂ representsthe distance between the point on the edge of plate 10 at which theforce F₂ is applied to the plate by upper jaw 16 and the force F₃ isapplied by lower jaw 17. Thus, the greater the ratio of the length of 1₁relative to the length of 1₂, the lesser is the force F₁ which is theforce applied to the force F₁ required to actuate the cables, orconversely the greater are the forces F₂ and F₃ and the grippingengagement of the plate.

Clamps C are normally relatively large castings of iron or steel andwhen gripping a plate edge during normal operation can be very effectiveto prevent misalignment.

Clamps C₁ and C₂ are arranged within channel 28 which extends the lengthof the guide system. The inside vertical or side faces 30 of channel 28act as side guides for clamps C₁ and C₂ along their length of travelwithin the system. Runout table 24 and the series of rolls 26 providesupport for plate 10 during its passage through the system.

A series of pulleys, P₁ and P₂, are provided as tail and head pulleys,respectively, and define the path of travel of cable R₁ to which tailclamp C₁ is attached. In like manner a pair of pulleys, P₃ and P₄, areprovided as tails and head pulleys, respectively, to define the path oftravel of cable R₂ to which lead clamp C₂ is attached.

In the embodiment shown, forming rolls 32, 40 and 42 of machine M areprovided to crimp and preform the edges of plate 10. In such anarrangement for example, roll 32 imparts the initial desired rollforming radius to the edges while rolls 40 and 42 insure conformity ofthe plate edges to the desired contour.

Cutters and bevelers 34, 36 and 38 trim, bevel and otherwise shape theedges of plate 10 to the width and edge contour required for the weldingoperation wherein the edges are joined to form the pipe section afterthe plate section is bent to a U-shape, and then to an O-shape prior tofinal welding into a finished pipe.

It can be appreciated from the foregoing type of edge treatment that themetal plate is subjected to a variety of lateral forces and that it isnecessary to provide an efficient and reliable latch and guide systemfor directing plate 10 through the system without misalignment orskewing.

As heretofore stated, the work that can be performed on the plate maytake many forms. Although the arrangement shown in M hereof is a machinefor preforming and edge trimming plates prior to forming heavy gaugepipe for use in high pressure steel pipe lines, many other operationsrequiring latch and guide systems to prevent misalignment and skewing ofa metal section as it is conveyed to, through and away from a formingoperation may be employed.

In the embodiment of the invention disclosed in the series of drawingsof FIGS. 5A through 5H steel plate 10 is shown in various positionswherein the clamping system of the invention is utilized during working.

FIG. 5A shows clamp C₁ and C₂ in a stationary and starting uprightposition ready to receive advancing plate 10 moving forward on conveyortable 24.

As plate 10 is moved forward by separate conveying means its leadingedge contacts clamp C₁ while in a stationary position at its top todepress it so that C₁ pivots at 12 thereby extending the rearmosttension spring 18 and permitting the cooperating forward spring tocompress, as shown in FIG. 5B. As plate 10 continues at uniform speed italso engages clamp C₂ and forces the clamp to move with it towardmachine M while maintaining sufficient cable tenison to insure adequategripping. Cable R₂ is moving at the same speed as the plate and withsufficient tension to enable clamp C₂ to maintain a firm grip on theleading edge of plate 10.

At the time of engagement of lead clamp C₂ with the lead end of plate10, the (See FIG. 5C) tail clamp C₁ is no longer depressed by plate 10and spring 18 returns it to an erect position. Cable R₁ then movesforward at a greater speed than that of the plate so that tail clamp C₁advances and engages the trailing edge of plate 10 as shown in FIG. 5D.Tension is then applied to both cables R₁ and R₂, so that they providetension on the clamps, C₁ and C₂ while moving at the speed of the platetoward machine M and thus maintaining the required clamping pressure.

Plate 10 when fastened in this manner continues to travel at constantspeed through the machine while clamps C₁ and C₂ restrain lateral motionas the plate is worked in the machine. Meanwhile, the clamps are alsorestrained from lateral movement by the side guides 28 and 30 whichextend along the length of the latch and guide system. FIG. 5E showsplate 10 while it is being worked in machine M.

After work has been completed on the side edges of the plate in themachine and the leading edges of the plate have passed from the machine,tension is applied in the reverse direction to both cables R₁ and R₂ toenable clamps C₁ and C₂ to disengage from the plate. Both clamps areshown in the disengaged position in FIG. 5F.

FIG. 5G shows clamp C₁ in the course of its travel back to its originalposition shown in FIG. 5A. Clamp C₂, which has been drawn away from theleading edge of plate 10 at a speed greater than that of plate 10,proceeds forward until it contacts stop 48 which depresses C₂ below thebottom of the plate to permit plate 10 to ride over it. Plate 10proceeds forward as shown in FIG. 5G while clamp C₂ is in a loweredposition and the plate rides freely over it.

Clamp C₁ which is returned by reversing the direction of cable R₁ whilethe speed of cable R₁ is increased. R₁ is thus returned to its originalposition and remains stationary to await the next plate. Cable R₂ alsoreverses direction and returns clamp C₂ to its starting position at anincreased speed, all as shown in FIG. 5H. When both clamps C₁ and C₂have returned to their starting positions they are ready to receive thenext plate for its travel through the system as heretofore described.

Motors 44 and 46 as shown in FIG. 1, or other suitable drivingequipment, are provided to actuate the respective pulley system in themanner described and independent of the plate conveying means.

The alternative embodiment of the invention shown in FIGS. 6A, 6B, 6Cand FIG. 7 utilizes a clamp and pulley system wherein the clamps andcables are designed to travel forward about the pulleys after the workhas been completed on a plate rather than returning the clamps byreversing the direction of the cables. This alternate arrangementdiffers from that heretofore described and as shown in FIGS. 1 through 5in that there are separate channels for each clamp and cable and in thatthere are two clamps on each cable. In other respects the latch andguide system is constructed and operates in substantially the samemanner as that heretofore described.

More specifically, clamps C₅ and C₇ which are adapted to engage thetrailing edge of plate 10' are mounted on the cable or chain strand R₃at points equidistant from each other. Also, clamps C₆ and C₈ which areintended to engage the leading edge of plate 10' are likewise mounted oncable R₄. Cable R₃ travels about pulleys A₁ and A₂ while cable R₄travels about pulleys B₁ and B₂. Any suitable system can be used formounting the clamps on the cables or chains about which they arepivoted. The mounting means disclosed in FIG. 2 can be usedadvantageously in the system in FIGS. 6A, 6B and 6C.

FIG. 6A shows clamps C₅ and C₆ mounted for engagement at the trailingand leading edges, respectively, of plate 10'. By the system cable R₃ ismoved at a speed greater than that of 10' so that it speeds up to engagethe trailing edge thereof immediately after the leading edge contactslead clamp C₆. The work then travels through the fabricating step asshown in FIG. 6B where the speed of movement of plate 10' and that ofcables R₃ and R₄ are the same.

After the working step the plate assembly with the engaged clamps movesout of the machine and the speed of cable R₄ is increased over that ofplate 10' and disengages from the plate. The speed of cable R₃ isdecreased to permit the plate moving to proceed ahead free of clamps C₅and C₆. Thereafter, cables R₃ and R₄ proceed at a uniform speed with allclamps spaced from the plate. Meanwhile, a new plate enters the systemand clamps C₇ and C₈, which cooperate in the same manner as clamps C₅and C₆, engage the trailng and leading edges of the new plate andproceed through the system as described.

FIG. 7 shows the arrangement of cables R₃ and R₄ within channels 50 and52, respectively, wherein they are held in a side by side relationshipwith a common side wall. The side walls of the channels serve as sideguides for the respective pairs of clamps that travel through the twinchannels. As in the case of the embodiment of FIGS. 1 through 5 thechannels of this alternative extend the length of the system between B₁and A₂ and are a single channel for cable R₃ and R₄ from A₁ to B₁ and A₂to B₂ respectively.

Although the operation of both of the embodiments of the inventiondescribed hereinabove contemplates that the speed of the cable carryingthe tail clamp shall be slowed to enable the clamp to lag behind themoving plate until the leading edge therein engages the lead clamp, andafter such contact the movement of the cable for the tail clamp isincreased to a speed greater than the plate to effect locking engagementbetween the tail clamp and the trailing edge, the operation may bemodified within the scope of the invention by adjusting cable speeds sothat the tail clamp engages the plate edge before the lead clampengagement is effected or the two clamps may engage the plate atapproximately the same time.

I claim:
 1. Apparatus for clamping and guiding a section of metal plateto restain lateral movement thereof as it travels longitudinally througha machine wherein said plate is subjected to mechanical work and toforces inducing lateral movement of the plate comprising,conveyor meansfor longitudinally moving the plates, first clamp means adapted toengage the trailing edge of said plate while moving on said conveyormeans, second clamp means adapted to engage the leading edge of saidplate while moving on said conveyor means, guide means for positioningsaid first and second clamps and extending along the length of saidapparatus wherein said lateral forces are effective, first cable meansto which said first clamp means are attached, second cable means towhich second clamp means are attached, a first pulley system foractuating said first cable means whereby said first clamp means and saidfirst cable means travel forward to engage the trailing edge of saidplate travelling toward said machine on said conveyor means to therebyplace said first cable means under tension and create a locking forcesufficient to lock said first clamp means on said plate, a second pulleysystem for actuating said second cable means whereby said second clampmeans travels forward after engagement with the leading edge of saidplate travelling toward said machine on said conveyor means to therebyplace said second cable means under tension and create a locking forcesufficient to lock said second clamp means on said plate and enable saidfirst and second cable means and clamp means to travel with said platethrough said machine, said first pulley system and said second pulleysystem being located adjacent to the longitudinal centerline of saidmetal plate and in a plane parallel to and spaced from the path oftravel of said metal plate to enable said first and second clamp meansto engage said edges of said plate at points spaced from thelongitudinal edges thereof to thereby leave said longitudinal edgesunobstructed for the application of mechanical work thereto, and meansfor disengaging said clamp means from said plate edges after said platehas passed through said machine.
 2. The apparatus of claim 1 whereinsaid guide means comprises a recessed channel beam having a pair ofvertically disposed side walls adapted to serve as side guides for saidfirst and second clamp means and to restrain lateral movement thereof aseach of said clamp means travels along the length of said machine. 3.The apparatus of claim 1 wherein means are provided to reverse thedirection of movement of said first and second cable means after saidfirst and second clamp means have been disengaged from said plate edgesto thereby return said clamp means to their original positions toreceive a new plate to be subjected to work.
 4. The apparatus of claim 1wherein said guide means comprises a channel beam having a pair ofrecessed areas having vertically disposed side walls, one of saidrecessed areas being adapted to serve as side guide means for said firstclamp means and the other of said recessed areas being adapted to serveas side guide means for said second clamp means, whereby both of saidside guide means restrains lateral movement of both of said clamp means.5. The apparatus of claim 1 wherein means are provided to permitcontinued forward movement of said first and second cable means afterdisengagement from said plate edges to thereby return said clamp meansto their original positions to receive a new plate to be subjected towork.
 6. The apparatus of claim 5 wherein said first and second clampmeans each comprise a pair of clamps affixed to each of said first andsecond cooperating cable means at equidistant points on each of saidcable means.
 7. The apparatus of claim 1 wherein each of said clampmeans is pivoted at a base affixed to one of said cable means and ismaintained in operative position by a pair of separate spring means, oneend of said spring means being attached to an end wall of said clampmeans and the other end of said spring means being attached at the otherend wall of said clamp means, and each of the other ends of said springmeans being attached to opposite ends of said base.
 8. The apparatus ofclaim 1 wherein each of said clamp means comprise an element having atone of its ends an opening in one end wall thereof and whereby it mayreceive a plate in gripping engagement therewith, and the opposite endof said clamp means being pivotally attached to cable means foractuating said clamp means.
 9. Apparatus for clamping and guiding asection of metal plate to restrain lateral movement thereof as ittravels longitudinally through a machine wherein said plate is subjectedto mechanical work and to forces inducing lateral movement of the platecomprising,conveyor means for longitudinally moving the plates, firstclamp means comprising a pair of clamps adapted to engage the trailingedge of said plate while moving on said conveyor means, second clampmeans comprising a pair of clamps adapted to engage the leading edge ofsaid plate while moving on said conveyor means, guide means forpositioning said first and second clamps and extending along the lengthof said apparatus wherein said lateral forces are effective, first cablemeans to which said first clamp means are attached, second cable meansto which second clamp means are attached, said first and second clampmeans each being affixed to each of said first and second cooperatingcable means at equidistant points on each of said cable means, a firstpulley system for actuating said first cable means whereby said firstclamp means and said first cable means travel forward to engage thetrailing edge of said plate travelling toward said machine on saidconveyor means to thereby place said first cable means under tension andcreate a locking force sufficient to lock said first clamp means on saidplate, a second pulley system for actuating said second cable meanswhereby said second clamp means travels forward after engagement withthe leading edge of said plate travelling toward said machine on saidconveyor means to thereby place said second cable means under tensionand create a locking force sufficient to lock said second clamp means onsaid plate and enable said first and second cable means and clamp meansto travel with said plate through said machine, and means to permitcontinued forward movement of said first and second cable means fordisengagement from said plate edges to thereby return said first andsecond clamp means to their original positions to receive a new plate tobe subjected to work.
 10. The apparatus of claim 9 wherein said guidemeans comprises a recessed channel beam having a pair of verticallydisposed side walls adapted to serve as side guides for said first andsecond clamp means and to restrain lateral movement thereof as each ofsaid clamp means travels along the length of said machine.
 11. Theapparatus of claim 9 wherein each of said clamp means is pivoted at abase affixed to one of said cable means and is maintained in operativeposition by a pair of separate spring means, one end of said springmeans being attached to an end wall of said clamp means and the otherend of said spring means being attached at the other end wall of saidclamp means, and each of the other ends of said spring means beingattached to opposite ends of said base.